The kinds of fats a lactating woman eats are reflected in her breast milk, and passed on to the nursing baby. An omega-3 fat called DHA is needed by the baby for brain and eye development. Nursing mothers who eat fish (rich source of DHA) have higher levels of DHA in the breast milk than mothers who do not eat fish. Some mothers do not like fish. Flaxseed oil is a plant source of omega-3 fat. The omega-3 fat is linolenic acid that the body can make into DHA. Adults do not make much DHA from linolenic acid. The nursing mother may be different. Because her baby needs a lot of DHA for brain and eye development, her body may make more DHA from linolenic acid. The purpose of this study is to find out the effect of taking flaxseed oil on the amount of linolenic acid that is made into the metabolically active fat DHA.